CBSE Class 8 Mathematics Introduction to Graphs Assignment Set 11

Question 1. The temperature of a patient, admitted in a hospital taken at different times in a day is given below. Draw the temperature-time graph for the data.
 

Answer:
To draw the line graph, take Time along the horizontal axis (X-axis) and Temperature (in \(^\circ\text{F}\)) along the vertical axis (Y-axis).
1. Mark the points corresponding to the given data pairs: \((4, 100)\), \((6, 101)\), \((8, 104)\), \((10, 102)\), \((12, 100)\), \((14, 99)\), \((16, 100)\), and \((18, 98)\).
2. Join consecutive points with line segments to obtain the required temperature-time graph.
In simple words: Plot time on the X-axis and temperature on the Y-axis, then connect the points with straight lines.

Exam Tip: Always label both axes clearly with appropriate units and choose a uniform scale.

Question 2. The velocities of a car at various times (in hrs) on a day are given below:
 

Draw the velocity-time graph for the above data.
Answer:
1. Represent Time along the horizontal axis (X-axis) and Velocity (in km/hr) along the vertical axis (Y-axis).
2. Plot the ordered pairs: \((5:00, 45)\), \((5:15, 50)\), \((5:30, 60)\), \((5:45, 40)\), \((6:00, 60)\), \((6:15, 70)\), \((6:30, 30)\), and \((6:45, 45)\).
3. Connect adjacent points using line segments to complete the velocity-time graph.
In simple words: Plot the given time intervals and velocities on a grid, then join the plotted dots with straight lines.

Exam Tip: Ensure time intervals on the X-axis are spaced evenly for accurate graphical representation.

Question 3. The sales of a shopkeeper for eight days of a month in any year is given below:
 

Draw the line graph depicting the above data.
Answer:
1. Take Date along the horizontal axis (X-axis) and Sales (in Rs) along the vertical axis (Y-axis).
2. Plot the points: \((1, 3300)\), \((2, 3390)\), \((3, 3450)\), \((4, 3490)\), \((5, 3370)\), \((6, 3470)\), \((7, 3590)\), and \((8, 4000)\).
3. Join the points consecutively with line segments to complete the line graph.
In simple words: Plot the dates against the sales amounts and connect the plotted points using straight line segments.

Exam Tip: When large starting values are involved on the Y-axis (like 3300), use a break symbol (\(\sim\)) on the axis if necessary to save graph space.

Question 4. The data regarding pressure (in Newton/\(\text{cm}^2\)) and volume (\(\text{cm}^3\)) of a gas are given below:
 

Draw a line graph depicting the pressure-volume of the above data.
Answer:
1. Take Pressure along the horizontal axis (X-axis) and Volume along the vertical axis (Y-axis).
2. Plot the ordered pairs: \((67.5, 100)\), \((71, 95)\), \((75, 90)\), \((79.5, 85)\), \((82.3, 82)\), \((83.5, 81)\), and \((84.5, 80)\).
3. Connect the plotted points consecutively with straight line segments.
In simple words: Plot pressure on the X-axis and volume on the Y-axis, then connect the points with line segments.

Exam Tip: Notice that as pressure increases, volume decreases; verify that your line slopes downward from left to right.

Question 5. The runs scored by two teams A and B in first 10 overs are given below:
 

Draw a graph depicting the data on the same axes in each case.
Answer:
1. Take the Overs (I to X) along the horizontal axis (X-axis) and the Runs scored along the vertical axis (Y-axis).
2. Plot the points for Team A and join them with a solid line.
3. Plot the points for Team B on the same axes and join them with a dashed or distinct colored line.
In simple words: Draw two separate line graphs for Team A and Team B on the same grid using different colors or line styles.

Exam Tip: Always include a clear legend or key to distinguish between multiple lines on the same graph.